Flea Control

What have y'all found to be the most effective predators of fleas? They get gnarly around these parts.  

What animal are you trying to protect?  Because fleas live on larger, warm-blooded hosts, the only effective predators would be some creature that the host is disposed to tolerate, like the birds you see on African rhinos in nature documentaries.  I don't know of any predators playing that role for dogs and cats.  Most flea treatments are based on killing the fleas through chemical or environmental means, like diatomaceous earth dehydrating the fleas and other invertebrates.